Former minister Alan Williams, who has died 50 years after first being elected to the Commons. Photograph: PA

Former Labour minister Alan Williams has died 50 years after first being elected to the Commons.

The veteran, who with 46 years of continuous service as an MP was father of the house when he stepped down at the 2010 election, was described by the former Welsh secretary Peter Hain as a “supreme House of Commons man”.

The 84-year-old had been in a nursing home in London for six months after suffering a stroke and died on Sunday night, said his successor as MP for Swansea West, Geraint Davies.

Davies said Williams had become a “local institution” and would be sorely missed by many.

He hailed him as a “kindly and private” man who transformed into a “ferocious cross-examiner” when it came to questioning ministers and others as a member of select committee, as well as leading questioning of the prime minister as chair of the liaison committee..

As prices and wages minister in the 1970s, he was “at the heart of the storm” of the industrial unrest that engulfed the James Callaghan government, Davies said.

“Alan Williams was a good friend for 18 years – a wise counsel and strong champion for Swansea for nearly half a century,” he said.

Hain said: “Alan was a supreme House of Commons man: diligent; questioning; challenging; always on top of the issues. He was highly respected across all political parties and I was indebted to him for his wise counsel even when we did not agree – for instance he was a critic of devolution where I was a big advocate.”

The son of a coal miner, Williams was a lecturer and broadcaster while seeking election, first unsuccessfully in Poole in 1959 and then Swansea five years later.

He held a series of ministerial posts under Harold Wilson and Callaghan and stayed on the frontbenches in opposition until 1988, including a spell as shadow secretary of state for Wales.

Noted as a consumers’ champion, he considered success in attracting Japanese investment to the UK a personal triumph of his time in government.

In 2005, when party colleague Tam Dalyell retired, Evans became the MP with the longest continuous service and tookthe title of father of the house.

He leaves a widow, Patricia, and three children including former international footballer Sian Williams who captained Arsenal Ladies.